大気・真空・液体中レーザーアブレーションにより生成された原子の挙動の光学的観測

We have been studying impurity atoms in superfluid helium (He II) using laser spectroscopic method. It is known that a depletion called “atomic-bubble” is formed when atoms are immersed into He II. Laser ablation is one of the effective methods to introduce atoms in He II, however, this process also causes vaporization of liquid helium due to the sudden transition of solid sample to high-temperature and high-pressure vapor. It is considered that it takes some time for atoms to form bubble states. Thus, we expect to observe time delay of atoms to get into He II.As the first step of the study above described, in this work, we aim to investigate dynamics of atoms optically by observing laser-induced fluorescence from atoms generated by laser ablation method in air, vacuum and liquid nitrogen.